fix(wallet): accept uppercase QR-scanned BOLT11 invoices on send

The send path detected and decoded uppercase invoices correctly (SendDialog's
isBolt11 lowercases first) but WalletService.sendPayment gated the bolt11
branch on a case-sensitive startsWith('ln'), so QR-scanned invoices (uppercase
bech32, e.g. LNBC...) fell through to the else and threw "Invalid payment
destination format" despite the UI showing a valid decode.

Detect BOLT11 case-insensitively by its HRP (lnbc/lntb/lntbs/lnbcrt) and send
the lowercase canonical form. The bare 'ln' prefix also incidentally matched
bech32 LNURLs (lnurl1...) and misrouted them to the bolt11 endpoint; matching
the full HRP closes that gap too.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/modules/wallet/services/WalletService.ts

@@ -240,21 +240,28 @@ export default class WalletService extends BaseService {
       let endpoint = ''
       let body: any = {}
       
-      // Determine payment type and prepare request
-      if (request.destination.startsWith('ln')) {
-        // Lightning invoice
+      // Determine payment type and prepare request.
+      // QR-scanned invoices are uppercase bech32, so detection must be
+      // case-insensitive. Match BOLT11 by its HRP (lnbc / lntb / lntbs /
+      // lnbcrt) rather than a bare "ln" prefix, which would also swallow
+      // bech32 LNURLs and misroute them to the bolt11 endpoint.
+      const dest = request.destination.trim()
+      const lower = dest.toLowerCase()
+
+      if (lower.startsWith('lnbc') || lower.startsWith('lntb') || lower.startsWith('lntbs') || lower.startsWith('lnbcrt')) {
+        // Lightning invoice (BOLT11) — send the lowercase canonical form
         endpoint = `${config.api.baseUrl}/api/v1/payments`
         body = {
           out: true,
-          bolt11: request.destination
+          bolt11: lower
         }
-      } else if (request.destination.includes('@') || request.destination.toLowerCase().startsWith('lnurl')) {
+      } else if (dest.includes('@') || lower.startsWith('lnurl')) {
         // Lightning address or LNURL
         endpoint = `${config.api.baseUrl}/api/v1/payments/lnurl`
         body = {
-          lnurl: request.destination.includes('@') 
-            ? `https://${request.destination.split('@')[1]}/.well-known/lnurlp/${request.destination.split('@')[0]}`
-            : request.destination,
+          lnurl: dest.includes('@')
+            ? `https://${dest.split('@')[1]}/.well-known/lnurlp/${dest.split('@')[0]}`
+            : dest,
           amount: request.amount * 1000, // Convert to millisats
           comment: request.comment || ''
         }